Merge pull request #935 from AlgorithmWithGod/suyeun84

[20250920] PGM / LV3 / N으로 표현 / 김수연

Author: ShinHeeEul

suyeun84/202509/20 PGM LV3 N으로 표현.md

@@ -0,0 +1,40 @@
+```java
+import java.util.*;
+
+class Solution {
+    public int solution(int N, int number) {
+        if (N == number) return 1;
+        List<HashSet<Integer>> dp = new ArrayList<>();
+        
+        for (int i = 0; i <= 8; i++) {
+            dp.add(new HashSet<>());
+        }
+        
+        dp.get(1).add(N);
+        
+        for (int i = 2; i <= 8; i++) {
+            // 순수한 수
+            StringBuilder sb = new StringBuilder();
+            for (int j = 0; j < i; j++) {
+                sb.append(N);
+            }
+            dp.get(i).add(Integer.parseInt(sb.toString()));
+            // 사칙연산한 수
+            for (int j = 0; j < i; j++) {
+                int k = i - j;
+                for (int num1 : dp.get(j)) {
+                    for (int num2 : dp.get(k)) {
+                        dp.get(i).add(num1+num2);
+                        dp.get(i).add(num1-num2);
+                        dp.get(i).add(num1*num2);
+                        if (num2 != 0) dp.get(i).add(num1/num2);
+                    }
+                }
+            }
+            if (dp.get(i).contains(number)) return i;
+        }
+        
+        return -1;
+    }
+}
+```